Method and apparatus for dispersing or drying fluent material in high velocity elastic fluid jets



1946- N. N. STEPHANOFF 2,413,420

METHOD AND APPARATUS FOR DISPERSING OR DRYING FLUENT MATERIAL IN HIGHVELOCITY ELASTIC FLUID JETS Filed Feb. 26, 1940 5 Sheets-Sheet 1 Dec.31, 1946. STEPHANQFF 2,413,420

METHOD AND APPARATUS FOR DISPERSING OR DRYING FLUENT MATERIAL IN HIGHVELOCITY ELAsTIc FLUID JETS Filed Feb. 26, 1940 5 Sheets-Sheet 2 Dec.31, 1946. N STEPHANOFF 2,413,420

METHOD AND APPARATUS FOR DISPERSING OR DRYING FLUENT MATERIAL IN HIGHVELOCITY ELASTIC FLUID JETS Filed Feb. 26, 1940 5 Sheets-Sheet 3 w //8 QI //6 0 /27 I26- 4' EA E S E E //0 //4 /24 la? /2/ /24 //2 /08 F76. 9.

2,413,420 RYING FLUENT JETS 5 Sheets-Sheet 4 "Dec. 31, 1946. N. N.STEPHANOFF METHOD AND APPARATUS FOR DISPERSING OR D MATERIAL IN HIGHVELOCITY ELASTIC FLUID Filed Feb. 26, 1940 Dec. 31, 1946. N. N.STEPHANOFF 2,413,420

METHOD AND APPARATUS FOR DISPERSING OR DRYING FLUENT MATERIAL IN HIGHVELOCITY ELASTIC FLUID JETS Filed Feb. 26, 1940 5 Sheets-Sheet 5Patented Dec. 31, 1946 METHOD AND APPARATUS FOR DISPERSING OR DRYINGFLUENT MATERIAL 'IN HIGH VELOCITY ELASTIC FLUID JETS Nicholas N.Stephanofl, Bryn Mawr, Pa., assignor to Thermo-Plastics Corporation,Camden, N. J a corporation of New Jersey Application February 26, 1940,Serial No. 320,788

Claims.

This invention relates to a method and appatus for drying, in a broadsense, material in the form of droplets or particles and, moreparticularly, to a method and apparatus for effecting such drying by theatomization of the material to be dried in a high velocity gas or vaporjet or jets.

In my application Serial No. 199,687, filed April 2, 1938, now PatentNo. 2,297,726, there is described the drying, in a broad sense, ofmaterial by atomization in high velocity gas or vapor jets. As pointedout in said application, in accordance with its disclosure drying andcomminution of materials may be effected to secure extremely minuteparticles. cerned with improvements in the methods and apparatusdescribed in said prior application; and for the broad action of highvelocity jets and other broader features of this method reference may bemade thereto.

The present invention is concerned primarily with particular problemsarising in effecting the results described in said prior application,more particularly with quite low pressure jets and economy of heat andgas. One of the objects of the present invention, for example, is theprovision of improved nozzle arrangements whereby deposition of dried orpartially dried materials is prevented in the vicinity of the nozzles.They are, in effect, what might be designated selfcleaning." Anotherrelated object of the invention is the provision of an apparatus on thewalls of which deposition of material does not occur,

' particularly in the handling of highly viscous materials relativelydiflicult to dry.

A further specific object of the present invention is the provision of amethod and apparatus for the more eifective handling of highly viscousmaterials of the nature of the filter cakes produced in the manufactureof pigments, such as, for example, titanium dioxide. In accordance withthe present invention, these pigments may be extruded into high velocityjets which effect not only the drying, but the disintegration of thepigment as well to produce an extremely fine product. This involves,furthermore, an improved method of obtaining the final product directlyfrom a filter cake without going through a preliminary drying of thefilter cake prior to grinding. When drying is effected in conven-'-tional fashion, agglomeration takes place, and the resultant driedmaterial is ground only with considerable diificulty. By the applicationof the present method, the grinding or disintegration is effected beforethe agglomeration can take The present invention is con- 2 place, and asuperior product of very uniform nature is thereby secured.

In accordance with the present invention, the drying and/or grinding iseffected while the material in comminuted form is maintained in arelatively restricted zone. Under such circumstances, it may besubjected to radiant heat,

in the form of infra-red or heat rays, which, in the case of a wetmaterial in comminuted form, is very efiective for applying heatthereto. By the use of radiant heat, a desired rise in temperature tofacilitate drying may be secured more efliciently than through heatingby the gas utilized for the drying. By an extension of the applicationof heat, actual calcination may be eifected for the productionofpartlcular materials, such as pigments which involve calcination tobring them into final form. Under such circumstances, there may beproduced in a single apparatus drying, fine grinding and calcinationwith direct collection of the final product.

In accordance with the arrangement described hereafter, wet grinding ofparticles can be effected with subsequent drying, as well as mere dryingof solutions or suspensions of sufficiently fine particles requiring nofurther grinding.

A further object of the invention is the production of chemicalreactions while one or more of 1 the reacting materials is in a fineatomized state.

A material undergoing drying, grinding and/or heating may be reactedwith a gas included in or forming an atmosphere into which it isdirected or, in fact, with the gas which may be used in whole or in partfor its drying and comminution. More important, however, is the securingof reaction between two non-gaseous substances by their intimateadmixture in finely comminuted state. Specifically, in accordance withthe present invention, the two materials in suspension or solution inliquid or even in a moderately finely powdered dry state, may beprojected in finely comminuted form and in accurately regulatedproportions into a common zone wherein violent admixture is eiiected andreaction accomplished. It will be evident that, since reaction time isdependent upon contact, reactions taking place relatively slowly ornecessarily in relatively dilute solutions under ordinary circumstancescan be caused to take place with great rapidity, and, if desired, finelycomminuted solid products may be secured directly without going throughthe usual-separate filtering, drying and grinding steps. As an example,lithopone may be produced by feeding into the apparatus zinc sulphate inthe form of a relatively thick paste with a similar paste of bariumsulphide. These two materials, finely atomized, are brought together ina common zone. where reaction may take place simultaneously with dryingand grinding. After drying is accomplished, the temperature may beraised while the material is still in suspension to produce calcinationand thereafter chilling and collection of the final product. By properproportioning of the reacting materials the reaction will be completewith substantially no proportion of either of the original materialsremaining. Thus in a single step there may be secured the production ofthe final product normally requiring a number of individual steps.

In the types of apparatus described herein, there may also beaccomplished the admixture of materials involving, for example, coatingof one material with another, as described in said application.

The above and other objects of the invention, particularly relating todetails of the method and apparatus, will become apparent from thefollowing description, read in conjunction with the accompanyingdrawings, in which:

Figure 1 is a diagrammatic sectional view through one form of apparatusdesigned for carrying out the objects of the invention;

Figure 2 is a transverse section of the apparatus of Figure 1 taken onthe plane indicated at 2-2 in said figure;

Figure 3 is a vertical sectional view through one of the nozzleassemblies illustrated in Figure 1;

Figure 4 is a transverse section taken on the plane indicated at 4-4 inFigure 3;

Figure 5 is a vertical sectional view of an alternative form of nozzleassembly particularly adapted for the more thorough grinding ofmaterials than that illustrated in Figure 3 and for the handling ofextremely viscous materials;

Figure 6 is a section taken on the plane indicated at 66 in Figure 5;

Figure 7 is a section taken on the plane indicated at 'I-l in Figure 5;

Figure 8 is a section taken on the plane indicated at 8-8 in Figure 5;

Figure 9 is a diagrammatic view illustrating a material proportioningapparatus designed for feeding materials to the dryer of Figure 1, andparticularly materials of highly viscous nature;

Figure 10 is a vertical section through still another form of nozzleassembly, particularly designed for the intimate admixture of reactingmaterials from the moment of their initial atomization;

Figure 11 is an inverted plan view of the nozzle assembly of Figure 10,illustrating particularly the relationships between the material feedingnozzles and the disintegrating jets;

Figure 12 is a vertical section through another form of nozzle assemblyfor dispersing materials embodying possibility of ready adjustment;

Figure 13 is a bottom plan view of the assembly of Figure 12;

Figure 14 is a sectional diagrammatic view illustrating an alternativeform of dryer, particularly designed for the utilization of radiantheat;

Figure 15 is a fragmentary sectional view taken on the plane indicatedat l5--l5 in Figure 14;

Figure 16 is a diagrammatic view, partially in section, showing anauxiliary grinding attachment applicable to the dryers of the precedingfigures; and

Figure 17 is a sectional view illustrating an alternative nozzleassembly desirably used in certain cases.

In the following description and claims it will be understood that wherethe term gas or air is used it is generally to be regarded as synonymouswith elastic fluid, i. e., it includes the vapor state of a substancebelow its critical temperature. As pointed out in said priorapplication, evaporation of a liquid, such as water, may be carried outnot only in a fixed gas, such as air, but in a'vapor, including thevapor of the liquid to be evaporated in a superheated or reducedpressure state, e. g., steam. Vapors as well as fixed gases may also beused in producing chemical reactions as described hereafter.Super-heated steam is a thoroughly effective drying medium for materialswetted with water or other liquids and, in fact, the desirable effectsof distillation in steam may be used to produce low temperature dryingof high boiling liquids which are immiscible with water. To simplify thedescription, reference may be made hereafter to specific gases or vaporswith the understanding that the terms used are to be broadly construed.Where drying is referred to herein, it will be understood that there isincluded the transition from a liquid to a solid or semisolid state,though that may not occur by evaporation of a liquid. For example,drying in this broad sense may occur by polymerization of a liquid, asthe result or chemical reaction, or by chilling of a molten liquid.

Referring first to Figures 1 and 2, there is disclosed therein anapparatus adapted, in the form illustrated, for drying and comminutionand, in addition, for performing chemical reactions. By slightmodifications, as will be apparent hereafter, involving, primarily,different nozzle constructions, it may be applied for other purposes.

The apparatus comprises a shell 2 preferably having a cone-shaped lowerend, indicated at l6, and surrounded by a, jacket 4 for heatingpurposes, as described hereafter. Located within the upper portion ofthe shell 2 are a pair of dispersing nozzle assemblies 6 and 8. Theseare directed within the shell, preferably as indicated in theconstruction lines in the figures, i. e., they are located closetogether and have their axes directed convergently toward each other(preferably so as to intersect not far from the assemblies) and somewhateccentrically with respect to the lower conical portion of the shell ina direction opposite the direction of flow of air having a general flowcountercurrent to the streams produced by the nozzles. This air isintroduced through a controlled pipe Ill and a venturi 12 whichcommunicates through the opening I4 with the lower portion of the conel6. By reason of the provision of the venturi, a smooth high velocityflow of air into the cone is produced, and by reason of the peripheralentrance it acquires a vertical motion to flow upwardly through theapparatus. By reason of the centrifugal action which occurs, it tends toflow along the walls as it progresses upwardly. The gas introduced atthe bottom of the apparatus may be hot waste gas under low pressure. Theheat of this gas may be primarily relied upon for the drying, thedispersing nozzle gas being cold or only moderately heated.

The lower portion or the cone l6 communicates at [8 with a receiver 20.In most normal operations of the device, nothing passes into thisreceiver 20, but it appears to form a gas cushion serving to smooth outirregularities in flow, while it is also present to receive any materialwhich might happen to reach it. But it the velocities in the shell areproperly adjusted, centrifugal separation may be caused to occur in thecone [8 with collection of the dried product in the receiver 20.

From the upper, preferably conical, end of the shell there extends theoutlet passage 22, which communicates peripherally at 24 with the upp rportion of a dust separator and collector, indicated at 26. The finalproduct separated in 26 is collected in the receptacle 28, while theoutflowing gas and vapor may escape through the passage 30 controlled bya damper 32. A side pipe 34, controlled by a damper 36 is adapted tolead a controlled amount of the escaping fluid through the heater 38 tothe jacket 4, whereby heating of the shell is accomplished with mosteffective utilization of the residual heat of the waste gases. Thejacket may discharge these gases through the pipe 40. In the event thatthey contain vapors desired to be recovered, suitable condensation mayfollow.

Referring to Figures 3 and 4, there is illustrated therein a form whichthe nozzles 6 and 8 may take which is found to be highly satisfactory. Atube 42 is provided for the feed of the material which is to bedispersed. While the arrangement is capable of dispersing substantiallyany type of material, it is particularly adapted for the dispersion ofhighly viscous material such as wet press cake, which may have to beextruded from the tube 42 under considerable pressure. The lower end ofthis tube is preferably rounded and restricted somewhat, as indicated,to secure a cleaning action, as will be described.

About the lower end of the tube 42 is located a chest 46 arranged to befed with steam, air or other vapor or gas at high pressure, and,usually, high temperature. Nozzles 50 are provided in this chest and aredirected as will be evident from consideration of the lines indicatingtheir axes in Figures 3 and 4, i. e., these axes are so directed as tojust miss the tip of the tube 42 and be substantially tangent to thelower end of th tube. From this arrangement it will be evident that aswirling array of jets will be provided.

It has been stated that the axes of the nozzles just miss the lower endof the tube 42. This, however, does not mean that the jets from thenozzlescompletely miss the tube 42, but actually the adjustment ispreferably such that the jets at their upper sides engage the tube atits tip. As a result of this, a violent disturbance is set up at the tipof the tube-and extends in the jet in the form of a wake made up ofvortices, and the wiping of the tube by the jets prevents anypossibility of having the material leaving the tube cake its outer sideor pass upwardly within the annular chest 46.

Above the chest 46 there is provided a conical enclosure, indicated at52, converging down, to a throat at the position of the chest. By reasonof the direction of the jets of gas from the chest, a high degree ofvacuum is produced in the cone, and by reason of its Venturi action, ahigh velocity of downward flow of gas within the throat is produced.Desirably the cone may be supported by means of directing vanes 56,giving to the gas flowing through the cone a swirl which may be in thedirection of, or opposite, the swirl produced by the jets from thenozzles 50, depending upon the action which is desired. In the eventthat it is desired to confine the dispersion which is produced,thedrotations thus secured may be in opposite directions. If spreadingis desired, rotations in the same directions are desirable. Thedivergence of the dispersed cone of material may also be controlled to asubstantial extent by direction of the jets 50 so as to be tangent tocircles of greater or less diameter.

The jets produced should conform to the conditions described in my priorapplication Serial No. 199,687; 1. e., the nozzles should be so formedas to produce at least acoustic velocities of the gas or vapor in thesejets. It is generally desirable that the nozzles be of abrupt type tosecure a maximum of turbulence to promote comminution or grinding,though smoother flow may be desirablewsecured by convergent and properlydivergent nozzles) if drying only is desired with a minimum of grinding,i. e., if the particles are not desired to be of too small size. Aspointed out in said prior application, acoustic velocities may besecured by the use of abrupt nozzles and 'superacoustic velocities bythe use of convergentdivergent nozzles. The acoustic velocitiescorrespond to the temperature and pressure conditions in the jet. Whenintensive grinding is to be accomplished, the jets from the nozzles 50are preferably caused to be tangentto a smaller circle than thatindicated, so that they impinge upon each other. In fact, they may bemade to intersect substantially at the axis of the tube 42, in

which case a maximum of turbulence and grinding is secured.

The action of a single nozzle assembly just described within thearrangement of Figure 1 is to produce along the general line of the axisof the nozzle assembly an extremely fine dispersion of the materialpassing through the tube 42. This dispersion is bounded by a surroundingatmosphere of gas passing at relatively low pressure and in largequantity through the cone 52 and is thus prevented from impinging uponthe walls of the shell. Before the dispersion can reach the lowerportion of the shell toward which the axis of, the assembly is directed,the expanding dispersion, now slowing down, will have met the outflowinggas from the opening I4, which, in the lower portion of the cone, has arelatively high velocity, slowing up as itenters the central portion ofthe shell. Here again, a protective layer of helically moving gas keepsthe dispersion from reaching the walls of the shell, and by the timesufficient diffusion can have occurred to bring any of the material incontact with the shell, it will have been dried and in such a fine statethat deposit on the shell does not occur. As the helix of flowing gaschanges to a spiral approaching the outlet 22, its linear velocity willbe maintained which means that, with reduction of radius, thecentrifugal forces on particles increase. Thus if larger incompletelydried particles reach this region, there will be a tendency to rejectthem from the outlet with a probability that in their circulation theywill be drawn into a nozzle assembly cone 52 to be recirculated into thelower portion of the drier.

In the securing of drying of materials, it is desirable first to have aslong a period of contact of the material to be dried with the dryingatmosphere as possible, and consequently relative movement of thematerial to be dried and the drying atmosphere. Both of these ends areachieved in the present apparatus, which involves both countercurrentand concurrent drying, The downwardly flowing dispersion has relativemovement with the upwardly flowing spirally moving gas and the path of aparticle in contact with a drying atmosphere is from the discloselyadjacent the assemblies.

ratus and then extends helically upwardly toward the outlet. Throughoutthis entire path,-

relative motion is produced, as by the meeting of the downwardly movingparticles or droplets with the upwardly flowing gas, and secondly by,

reason of the turbulence set up by centrifugalaction in the helicalflow. It maybe pointed out, furthermore, that larger particles will havegreater inertia and hence will reach the lowermost por-v tions of theshell which are not reached by the smaller particles or droplets. Inthis fashion, the

larger particles or droplets are brought into contact with the upwardlyflowing gas before it becomes even partially saturated by evaporation ofliquid from the finer particles or droplets. Uniform effective drying isthereby promoted.

This action is described for a single nozzle assembly only, as would beused for ordinary drying. In the case of two nozzle assemblies, asillustrated, whether for mere drying or for the production of chemicalreaction or coating, the action so far as the shell is concerned isquite similar, though the dispersions may be caused to merge The matterof reactions will be referred to in greater detail hereafter.

In Figure 5 there is illustrated another form of nozzle assemblyparticularly desirable where viscous material rather than a mobilesolution or suspension is to be dispersed. In this assembly a Venturientrance passage 58 is assembled to a group of gas chests 60, 64 and 88,the inner surfaces .of which continue the Venturi passage begun by theentrance 58. The gas chests are respectively provided with nozzles 62,B6 and 10, of which, for example, as indicated in Figures 7 and 8, thenozzles 62 and I0 may be directed to produce a rotation of the gas in aclockwise direction, viewed from above, and nozzle 68 may tend toproduce rotation in a counter-clockwise direction. The axes of thesenozzles are disposed as indicated in the figures, and if reversedirections of rotation are imparted by the successive sets, intenseturbulence and comminution' of the material to be dispersed isefl'ected.

A central tube 12 is provided for the introduction of the material, thistube being restricted, as indicated at 14, at its lower end. Thematerial enters this tube from the chamber 16, to which entrance isaiforded through the central tube 18 and a group of tubes 80communicating with the chamber 16 through eccentrically directedpassages, indicated at iii in Figure 6. This arrangement providesconsiderable flexibility for use with various types of materials. If thematerial to be introduced is plastic in nature but flows comparativelyreadily, it may be forced into the chamber 16 through either the axialor peripheral entrances and extruded therefrom through the tube 12 intothe region of the jets issuing from the gas nozzles. In such case ofextrusion, it is not necessary to have the upper jets wipe the lower endof the tube, as illustrated in Figure 3, the extruded rod of materialmeeting the jets and being broken up by them as it projects thereinto,If the material is more viscous, so as to be desirably diluted with gasas it leaves the tube 12, the material may be forced into the chamber 16at 18, there to meet jets of gas issuing from the passages or nozzles8|, so that there will emerge from the tube 12 at high velocity thematerial already substantially suspended in the gas. Liquid for itsdilution may be introduced instead of the gas. Alternatively, thematerial to be dispersed may beintroduced through the peripheral tubesand approach of the tube 12 to the dispersing jets'may be varied-tosecure themost desirable action, de pending upon the nature andparticularly the viscosity of the material to bedlspersed. In the caseoflow viscosity material it'may be located to be wipedby the uppermostjets as in the modification of 3 to produce suction and turbulence. Itmay'be'noted that even if the jet is-of smooth flowcharacteristics,'such as a jet of superacoustic velocity produced by aDe Laval nozzle, turbulence will result as it breaks away from a surfaceat the feed tube tip in contact with which it flows. v v

As in the case of the modification of Figure 3, a high velocity of flowtakes place through the venturi approach, cleaning out of the passagesany material which might tend to pass upwardly and forming, in effect, asheath of gas about the dispersion promoting evaporation and preventingits deposition in wet state upon the walls of the apparatus.

To secure most intense grinding in the type of assembly illustrated inFigure 5, the jets are caused to impinge upon each other to a maximumdegree. The material so ground in the wet state, then in a, finelydispersed form, is dried in the region through which it subsequentlytravels.

It will be evident that with the use of single dispersing nozzleassemblies in the apparatus of Figure l or the use of a plurality ofsuch assemblies handling the same materials, not only may drying beeffected, as indicated above, but reactions with gas may be produced ifthe gas entering the casing 2 at H and/or the gas used for dispersion isadapted to react with the material dispersed. Thus, for example, vaporsof formaldehyde may be caused to react with phenolic substances to formplastics recovered directly in a finely divided form suitable forintroduction into molds. Similarly, other vapors or gases, such asammonia, other aldehydes, etc., may be reacted with sprayed liquids.

More important than the reactions with gases, however, are the reactionsachieved between materials fed selectively through a plurality of nozzleassemblies or dispersed individually in a single assembly, as describedin greater detail below. The speed of chemical reaction is dependentlargely upon the surface contact of the reacting materials, particularlyin organic reactions which are frequently very slow when occurringbetween liquids, liquids and solids, or solids and solids in solutionsor suspensions. If such materials are finely dispersed, and, in suchstate, admixed, or, alternatively, partially or completely admixed andthen immediately dispersed, the reactions are greatly accelerated. Thespeeding up of reactions, however, is not the sole advantage. If areaction, for example between two salts, results in the formation of aprecipitate, the final product may only be secured from a reaction insolution through the medium of filtration, washing and drying; and if afinely comminuted product is required, this drying is generallynecessarily followed by grinding because, in the precipitation insolution and in the filtration, agglomeration occurs. brought togetherin finely comminuted form, however, while wet (either in solution orsuspension) the reactions will take place with the formation of productsin finely comminuted form. If drying then occurs, a line powder isproduced which,

If the materials areno material which need be washed from the solidproduct, the result is the direct production of an extremely finepowder. If, on the other hand, a soluble salt remains which must bewashed out, the dried powder can be subjected to washing and can then befiltered, washed and dried, generally without further agglomeration,since it has already passed into a stable physical state, nonconduciveto the further growth of the particles. Such a wet washed powder can bedried by a subsequent operation in the machine illustrated.

Generally, in reactions in which one material is not a gas, it isnecessary for economy, if not for the obtaining of a desired finalproduct, that the reacting materials be fed in rather clcsey relatedproportions. These proportions need not necessarily be chemicalequivalents but may involve predetermined excesses of one or morematerials to secure most effective reaction in accordance with the lawof mass action. In conventional batch processes or even continuousprocesses inwhich the time of reaction is indefinitely long and thoroughintermixtu e may be leisurely caused to occur, it is sufiicient that thematerials be measured out in desired proportions and mixed togethereither at one time or progressively. 'In the described apparatus,however, it will be evident that a particular small amount of materialpassing from one nozzle assembly will be completely out of the reactionzone in a time of the order of a fraction of a second to not more than afew seconds, and hence it is necessary to feed the materials continuousy in cont nuously closely regulated proportions to insure that the reacton will be completed or have proceeded to the desired extent beforedrying occurs and, at any rate, while the materials are in suspen ion,i. e. before they come to a condition in which agglomeration can occurin a separator or collector. To this end, there may be provided aproportioning apparatus of the type illustrated in Figure 9 for feedingthe res ective reacting materials to the nozzle assemblies 6 and 8through the feed tubes I2I and I23.

In Figure 9 there is indicated at 82 a shaft suitably driven at asuitable high rate of speed and connected to discs 84 and 86, whichcarry radially adjustable crank pins 80 and 90, desirably in the samephase relationships, though this phase may be desirably adjustable, asindicated hereafter. These crank pins operate in slotted cross-heads 92and 94, respectively, carried by plungers 96 and 98, which, at theirlower ends, are reduced to provide pistons I and I02, working incylinders I04 and I06. These cylinders receive, respectively, throughconnections including check valves I08 and I I0, materials from supplytanks I I6 and H8. If highly viscous materials are being handled, gaspressures may be maintained on the materials in these tanks through themedium of connections I20 and I22. In such case, the rate of feed may becontrolled by control of the pressures, as indicated by suitable gauges,to insure that on the upstroke of each piston the corresponding cylinderwill be filled with material and not have therein spaces in which mayexist partial vacuum. Stirring means may be present in tanks IIS and II8 to the pistons it may be desirable to adjust the maintain uniformsuspensions or mixtures there- The cylinders discharge throughconnections I24 and I26, containing discharge check valves H2 and Ill(sufliciently resisting direct passage of material due to pressure intanks I I6 and I I8) .into containers I25 and I21, in the nature of airdomes to smooth out the fluctuations, and from these cylinders thereextend connecting tubes I 2I and I23 to the nozzle assemblies such as 6and 8 of Figure 1.

By the use of this apparatus and the proper adjustment of crank pins 88and 90 radially, and

with a suitable high velocity of rotation of the shaft 82, coupled withsmall size of cylinders I04 and I05, there can be insured a carefullycontrolled delivery of proportionate amounts of materials through theassemblies, the amounts being so proportioned as to secure the desiredreaction. Substantially continuous streams of materials in finelysuspended form will issue from the nozzle assemblies at an accuratelypredetermined rate in the case of each to insure complete reaction inthe limited zone afforded by the flow through the apparatus. Ifmaterials of different viscosities are fed, then to insure simultaneousdelivery of portions corresponding to strokes of phase relationship ofthe crank pins because of slight lags occurring in passage of the moreviscous material to its nozzle assembly due to elastic efiects in thefeed line.

As an example of the type of chemical reaction which may be produced,there may be mentioned the production of lithopone by the spraying intoa common reaction zone of an aqueous paste of zinc sulphate and anaqueous paste of barium sulphide. In the feeding of these materials,stirring may be used to maintain the material fed of uniform compositionand adjustment of feeding means such as that of Figure 9 made uponanalysis of the materials to insure their feed in equivalent quantities.The reaction between the two constituents will take place with greatrapidity, in view of the large surfaces oifered for reaction by thedroplets or particles, and the result will be a dry cloud of fineparticles composed of zinc sulphide and barium sulphate. This cloud maybe passed through a calcining zone provided either in a separateapparatus or by the introduction of sufiiciently hot gases, for example.in the bottom of the apparatus of Figure 1. If chilling of the particlesis desired, large quantitles of air at ordinary temperature may beadmixed with the suspension prior to its reaching the separator. It willbe evident that the reaction may take place in inert gas or in areducing gas if the temperatures used are such that detrimentaloxidation might possibly take place in air. In the case of chemicalreactions, not only.

can there be removed by evaporation liquid solvent, but there may alsobe removed volatile solid products of a reaction if the temperaturerequired is not too high to cause damage to the other particles. Forexample, in the precipitation of chemical bases by the use of ammoniumhydroxide, the resulting ammonium salt may be volatilized together withthe water used for solution or suspension and the base in a dry form andfree of ammonium salt recovered. In such case, the volatilizingtemperature must be maintained through the dust collector, and the spentvapors may be fractionally or wholly condensed to recover material ofvalue such as, in the example just mentioned, ammonium salts.Evaporation or l1 volatilization of products of many reactions willcause them to approach substantial completion according to the law ofmass action.

In the operation of the apparatus in Figure 1 in accomplishing achemical reaction, the proportioned amounts of materials Intermix in theregion about the dash lines indicated in that figure. Generallyspeaking, the materials will be initially moist with aqueous or othersuspending liquid or solvent, though, of course, either or both may becompletely in solution. As the reaction proceeds, evaporation of thesolvent or suspending liquid simultaneously occurs and this evaporationmay be substantially complete before the suspended material reaches thecone I6. At this point its velocity in a downward direction will begreatly reduced, and as it meets the relatively high velocity vorticalflow in the cone the direction of movement of the suspension will beupward in a spiral direction adjacent the walls. The adjustmentshould besuch that, before any particles can reach the walls 2 they will havebeen dried so as not to adhere thereto. The suspension carried upwardly,with centrifugal separation and recirculation of large particles throughcones such as 52, will pass out through connection 22 to the separator26. In some cases, some of the material will enter the receiver 20. Moreusually, if a fine product is desired, little or no material will reachthis receiver.

Not only chemical reactions but physical admixture or coating andquasi-chemical reactions may be produced. For example, lakes may beformed by spraying together a metallic base and a dye solution, theresulting pigment in a fine state resulting directly as a product. Orparticles intended to form the disperse phase of an emulsion may becoated with a dispersing agent, such as a soap, to produce a fine powderwhich forms an emulsion directly upon introduction into a liquid.

Polymerizations may also be effected, for example, the catalyticpolymerization of liquid isobutylene, by dispersing it into admixturewith a catalyst such as aluminum chloride or boron fluoride at a lowtemperature (0 F. to --40 F.) The viscous resulting product may beadmixed with other materials while in the dispersed state and before itmay engage and stick to the walls of the apparatus.

In the case of reactions of materials with gas, a similar action takesplace, and a similar flow of suspended material occurs also in the caseof ordinary drying, in which there may be used only a single nozzleassembly. Similar actions occur in the use of the other nozzleassemblies heretofore described.

In the case of the nozzle assembly of Figure 5, it will be evident thatgreat freedom of choice in the admixture of materials may be had.Partial admixture may occur in chamber I6 and tube I2 accompanied bypartial reaction. Dispersion may occur before any, agglomeration cantake place. Reacting gas or gases may be introduced through one or moreof the nozzle groups 62, 66 and I0.

While heating may be accomplished by the introduction of hot gases foratomization through the nozzle assemblies in Figure 1 and by theintroduction of hot gas through the passage I2, and by reason of theprovision of a hot jacket indicated at 4, materials in fine suspensionare adapted to be quite efficiently heated by the use of radiant heat.The use of radiant heat for directly heating suspensions eliminates thelosses involved in first heating a drying atmosphere of I58, asillustrated.

gas, passing this to a drier and then producing a heat interchangebetween the gas and the material to be dried. By the direct applicationof radiant heat to the suspension, losses are avoided, and the heat maybe more emciently utilized, since it must not be brought to the liquidto be evaporated through the medium of a gas of low specific heat andpoor heat absorbing qualities such as air. Radiant heat is readilyabsorbed by dispersions, particularly when they contain solid particles.In the formation of dispersions as described herein, temperature dropsgenerally occur at the nozzles due to expansion, and radiant heat may beutilized directly at these points to raise the temperature of thedispersion to the proper degree.

In the apparatus of Figure 14, the arrangement is such as to impart heatto a material being dried, or to materials undergoing chemical reaction,by means of radiant heat to a primary extent. Such chemical reaction maybebetween two materials or may consist of polymerization of a singlematerial. For example the polymerization of styrene may be started whilethe styrene is in a dispersed state to form polystyrene resin in afinely comminuted form. In the case of an exothermic reaction such asthis polymerization, the application of the radiant heat is localized sothat the dispersion rapidly passes from the region of its application,and into a cooler region.

In the apparatus of Figure 14, there is provided a shell I28 having adome shaped top I30 surrounded by a combustion gas chamber I32, withinwhich is burned fuel such as oil from burners I34, receiving their airthrough passages I36. These products of combustion may raise the domeI30 to a temperature desired to secure the necessary amount of infra redor heat radiation. The products of combustion may escape through theoutlet I38.

The lower end of the shell has a. conical shape I40 and communicateswith a separator I42, of conventional type from which there extends theoutlet I. As indicated diagrammatically to the left of this figure,vapors or gases from which the solid material has been separated may bepumped by means of a pump or blower I 48 into the top I50 of. a jacketI52 surrounding the combustion chamber I32. This jacket I52 has a skirtportion I54 from which the gas and vapors heated by passage over thecombustion chamber I32 may enter the shell through opening I56, beinggiven a rotary flow by guide vanes Inasmuch as increasing amounts ofvapors are being continuously formed by the evaporation ofv liquid, acontrolled escape I46 is provided to bleed from the apparatus the excessvapors. The material to be dried may be introduced through the nozzleassembly I60. If chemical reactions are to take place, a plurality ofsuch assemblies may be provided as illustrated in Figure 1.

It will be evident that the material will be heated in this apparatus toa very substantial extent through the medium of radiant heat from thesource surface I30. Further heating, of course, takes place by theintroduction of the heated vapors and gas at I56. The dispersing gas orvapor may also be heated to a considerable extent'. By the provision ofthe recirculating arrangement for the gaseous fluid, the efficiency ofthe apparatus is greatly increased, since the heat of the hot gases isnot entirely lost. The heat from the escaping gases at I46 may 13 betransferred through heat transfer apparatus to preheat the fluid usedfor the dispersing or to preheat the solutions or suspensions ofmaterials to be dried or reacted.

By the use of the arrangement shown, dust and wet particles will notreach the radiating surface I38 and the dispersion or fog will have theradiation playing down upon it.

While radiant heat may be provided from a hot surface such as I38, itmay be supplied, particularly .if infra-red radiation is primarilydesired, from infra-red electric bulbs located in a dome such as I38along with suitable reflectors. Infra-red radiation is particularlyeffective for the heating of fogs which are deeply penetrated by it tosecure thorough heating of a dispersion. Flames open to the dryingregion may also be used for supplying radiant heat without danger ofcontamination of the product with combustion gases if a pressure ismaintained to drive the combustion gases away from the drying zone andto maintain the product of the drying away from the zone in which it canremain only by incorporation in a jet. For example, if open flames areprovided in the location of the dome I38, and a slight excess ofpressure is maintained therein, with suitable outlets for the productsof combustion, this separation may be maintained. In many cases,however, separation is quite unnecessary, and in such case, the radiantheat of fiames may be used as well as direct heating by the products ofcombustion which may pass with the evaporated vapors to the outlet andcollector. Such an arrangement is particularly desirable wherecalcination of the product in a finely suspended state is desired, inwhich case fiames may be projected directly into the dispersion. Heatmay be quite locally applied, for example being focussed on the regionin which a dispersion is being formed by the use of a heating bulb andreflector, when it is desired merely to start a reaction which isexothermic in character, as in the case of certain polymerizations.

The reaction may be exothermic to such extent that, after it begins,cooling should be effected. This may be done in the apparatus of Figure1 by introducing cold, rather than hot gas at I4. Such introduction ofcold gas is also used where the apparatus is used for the chilling ofdispersed droplets of molten material. In the case of the latterprocedure, if it is desired to prevent adherence of solidified dropletsof bituminous or waxy materials, a suitable dust-laden atmosphere may beintroduced from outside the apparatus by means of a conduit connected toone or more of the funnels such as 52. The dust will coat the particlesof plastic material preventing their adhesion. The dust may consist of adispersing material so that the final product when mixed with a liquidmay form directly a dispersion or emulsion. I

In the types of apparatus illustrated in Figures 1 and 14, the productsof either drying or reaction will generally be in an extremely finestate, but sometimes the fineness will not be sufiicient. Accordingly, afurther grinding of the product may be desirable, and for this purposethere may be added the apparatus illustrated in Figure 16.

At I16 in this last figure, there is illustrated a cone which may beeither the cone I6 of Figure 1 or the cone I48 of Figure 14, in eithercase designed to receive particles which are to be further ground. Inthe case of the apparatus of Figure 1, for example, the velocity of flowthrough the passage I2 may be so controlled that the upward flow withinthe chamber 2 is so low as to carry through the outlet 22 only very fineparticles. In such case, the; larger particles may settle down throughthe cone such as I18. The pressure within the apparatus is then alsodesirably increased (by restriction of the upper outlet) so that in thecone I18 will be secured a sufficient pressure to cause the gas thereinand suspended particles to be forced through the extension II8 andnozzle openings I88 in an endless tubular passage, as illustrated. Thesenozzles may be controlled by gates indicated at I82, to secure greateror less velocity of entrance of materials into the passages I88 and tocontrol the pressure drop.

It will be noted that evaporation of liquid will increase the pressurein the drying apparatus if the outlet is restricted and will furnish aconsiderable volume of gas to form the jets in the auxiliary grindingapparatus. The material is already entrained in the gas so that highvelocity jets may be produced by nozzles I88 without regard toentrapment of material. Material which is originally quite wet is veryeffectively handled by this apparatus because of the large quantity ofsteam produced by evaporation in the drier which becomes available forthe grinding jets.

The tubular apparatus comprises a lower bend I84 and an upper bend I88connected by straight portions I88 and I82. An outlet I94 communicateswith the inner side of the straight down fiow passage I82 and serves tolead centrifugally separated fine material into the separator I88,communicating with the collector I88 and the outlet pipe 288. Within thetubular grinder the final comminution of the material takes place in thehigh velocity auxiliary jets issuing from nozzles I86. In the upper bendcentrifugal separation takes place with the result that the heavierparticles are thrown outwardly and hence caused to recirculate throughthe device, while the finely ground particles may be carried through thepassage I94 of the separator. The operation of this tubular mill isdescribed in my a plication Serial No. 235,139, filed October 15, 1938.The nature of the comminutlon occurring therein and the constructioninvolved are described in said application.

For the purpose of securing a zone of reaction extended to the maximum,it is desirable that the reacting suspensions should be in intimatecontact substantially from their initial dispersion. Accordingly,instead of having independent assemblies, such as 6 and 8, sprayingtheir suspensions into reactive admixture, it is more desirable toutilize an arrangement such as that illustrated in Figure 10. In thisfigure a series of tubes, 282, 284 and 288, of any suitable number,terminate closely adjacent each other in outlets 288, 2I8 and 2I2. Thematerial issuing from these outlets is engaged by high velocity jetsissuing from nozzles 2I4, 2I6 and 2I8. In a preferred arrangement, thenozzle openings are duplicated in each of these, as indicated at 228,and are directed so as to converge substantially at the location of theoutlets of the tubes 288, 2I8 and 2I2. Preferably, these high velocityjets should barely wipe these tips to secure the most effectivedispersion of the materials. The directions of these jets'are preferablyas illustrated in Figures 10 and 11, i. e., downwardly and tangentiallyto a circle in which the openings of the tubes lie, so that a downwardand spiral motion will be given to the dispersions, very subtermixture.Additionally, as in the case of the nozzle assemblies already mentioned,a cone 224 is provided to form a Venturi approach, the throat of whichis in the vicinity of the formation of the dispersion. Thus a largevolume of gas sweeps downwardly tending to confine the dispersion andshield it as a dynamic barrier from the walls of the apparatus. Thedispersing arrangement just described will, of course, take the place ofthe nozzle assemblies heretofore described.

For drying purposes, especially where attendant grinding is desired, adesirable form of nozzle assembly is that of Figures 12 and 13. In thismodification, a central member 226 has an opening fed by a tube 228 witha suitable elastic fluid. The passage through 226 is preferably in theform of a nozzle having a throat 232 and a diverging outlet 230. At itsoutside the member 226 is formed as illustrated, with a conical lip at234. Threaded to its exterior and securable in adjusted position by alock nut 235 is a sleeve member 236 provided with an inner conicalsurface corresponding to the surface 234 and providing with it a conicalshaped opening 242 which can be adjusted, as will be obvious, by axialmovement of the sleeve 236 relative to member 226. Between the twomembers 226 and 236 there is provided the chamber 240 to which thematerial to be dispersed may be fed through connection 238. The sleeve236 supports through the medium of arms 244 a cone 246 threaded at 248to support the elastic fluid chest 250 adapted to receive the dispersingfluid through connection 252 and project it at high velocity through thenozzles 254. The direction of these nozzles may be understood bycomparison of Figures 12 and 13, in which' it will be noted that theaxes of these nozzles are directed substantially tangential to theconical outlet 242 as viewed in inverted plan in Figure 13 and in adownward direction as viewed in Figure '12. The jets from these nozzleswill wipe the metal walls bounding the opening 242 and, it will benoted, will strike all parts of the conical sheet of the material to bedispersed issuing from the opening 242. The gas drawn at high velocitythrough the cone 246, and received either from the interior of theapparatus or through a conduit communicating with the exterioratmosphere or a source of relatively low pressure gas, will again forman outer dynamic barrier while the gas flow through the nozzle 230 athigh velocity will engage the inner face of the dispersed sheet, so thatthe result is a cone of dispersed material engaged both exteriorly andinteriorly with gaseous fluid to produce a high rate of evaporation. Inview of the conical nature of the dispersion produced by this nozzle, itis not so well adapted to the production of chemical reactions byassociation with another of similar type as are the nozzles discussedpreviously. However, if there is no objection to having the reactingmaterials intermixed immediately before dispersion, a mixture thereofmay be formed in the chamber 240 and dispersion with proper reactionwill then occur.

This dispersing assembly is particularly useful with heavy viscousmaterials because of the thin sheet presented essentially edgewise tothe nozzles. In the case of feed of heavy rods of viscous and adherentmaterial, for example from the nozzle of Figure 3, the impact of the jetwith the material may use up so much of its energy stantially promotingtheir almost immediate inthat complete fine uniform dispersion may notoccur. This difilculty is met in this last arrangement, in which thethin sheet of material is sheared edgewise.

The various dispersing assemblies described involve in common thedirection of a plurality of high velocity jets at acute angles to arestricted region of a plane towards the same side thereof but withtheir axes in non-intersecting directions to form a dispersion ofmaterial flowing from said region in the fluid from the jets. The axesof these jets are preferably in the same skew direction relative to aline normal to said region.

, In Figure 17 there is shown still another form of nozzle assemblydesigned for the eflective dis-- persing of relatively low viscositymaterial. This comprises a tube 266 having a head 262 of smooth form,preferably spherical or ellipsoidal in nature. This head 262 is providedwith a plurality of openings, indicated at 264. Directed toward therearward portion of the head are nozzles 268 on the ends of tubes 266.Any suitable plurality of such nozzles may be provided, or even one maybe used if completely symmetrical results are not required. Gas issuingfrom these nozzles tends to spread itself about the head 262 and thenstreams therefrom, carrying with it material which is pulled from thehead by the suction in the vicinity of the openings 264 set up by thebreaking away of the stream from the surface along which it flows. Itmay be remarked that this creation of suction to a considerably greaterdegree than in the preceding modifications makes this type ofarrangement particularly attractive when it is not desired to feed thematerial to be dispersed under pressure,

In the case of all of the dispersing assemblies it is desirable to haveone or more high velocity jets of elastic fluid wipe over a convexsurface in the region of an opening in the surface through which thereis introduced the material to be dispersed, so that the stream of fluidbreaks from the surface in the vicinity of the opening to entrain andform a dispersion of the material. An exception is the apparatus ofFigure 5 in which a highly viscous material such as filter cake may beprojected into the path of jets by extrusion.

The gas nozzles in all the forms of the apparatus disclosed herein aredesirably of the types described in detail in my application Serial No.199,687, the particular forms used depending upon the type of flowrequired in the case at hand.

What I claim and desire to protect by Letters Patent is:

l. The method of drying material comprising passing material to be driedthrough an opening in a convex surface, and directing a high velocityjet of elastic fluid to wipe, subsequently to its formation, over saidconvex surface in a direction in which said surface has substantialcurvature and in the vicinity of said opening so that the stream offluid breaks from the curvature of said surface adjacent said opening toentrain and form a dispersion of the material in fluid from the jet.

2. Apparatus for forming a dispersion of material comprising a pluralityof series of nozzles discharging into a relatively restricted passage,and means for feeding material to be dispersed to the nozzles of one ofsaid series, all of said nozzles being directed in the same generaldirection in said passage, so that the dispersion formed by the firstseries passes in turn through the jets issuing from the nozzles of thesubsequent series,

17 said series of nozzles being arranged to produce helical flow of thedispersion within said passage.

3. Apparatus for the dispersion of material comprising a receiver, meansproviding a converging fluid guiding region within said receiver andspaced at least in part from the walls thereof, both ends of said meansbeing open to fluid within the receiver so that fluid leaving one end ofsaid region may enter the other end thereof, means for producing in thevicinity of the throat of said region a high velocity jet of elasticfluid directed away from the enlarged entrance portion of said regionand arranged to induce flow through said region, and means forintroducing material to be dispersed into said jet.

- 4. Apparatus for forming a dispersion of material comprising meanshaving a convex surface provided with an opening through which thematerial may emerge at a low speed, and a nozzle spaced from saidsurface for directing a high velocity free jet of elastic fluid having asubstantially definite linear direction of flow to wipe over said convexsurface in the vicinity of said opening, so that the stream of fluidbreaks from said surface adjacent said opening to entrain and form adispersion of the material in fluid from the jet.

5. Apparatus for drying material comprising a receiver having its upperend communicating centrally with a discharge passage, elastic fluidguiding means located inside the upper portion of said receiver at oneside of the discharge passage, means for providing a dispersion ofmaterial flowing at high velocity in a downward direction from saidelastic fluid guiding means and serving to induceflow therethrough, andmeans for providing a spirally ascending flow of elastic fluid throughsaid receiver, said guiding means communicating at its upper end withthe region in the upper portion of the receiver so that in .jection offluid through the guiding means is efi'ected from a portion thereofmoving spirally inwardly towards said discharge passage.

6. The method of drying material comprising directing a plurality ofhigh velocity jets of elastic fluid into a receiver, said jets beingdirected, convergently with respect to each other, at acute angles to arestricted region of a plane towards the same side thereof but withtheir axes in non-parallel and non-intersecting directions, andintroducing into said jets material to be dried, thereby forming adispersion of said material flowing from said region in fluid from thejets.

7. The method of drying material comprising directing a plurality ofhigh velocity jets of elastic fluid into a receiver, said jets beingdirected, convergently with respect to each other, at acute angles to arestricted region of a plane towards the sam side thereof but with theiraxes in non-parallel and non-intersecting directions and in the sameskew direction relative to a line normal to said region, and introducinginto said jets material to be' dried, thereby forming a rotatingdispersion of said material flowing from said region in fluid from thejets.

8. The method of drying material comprising directing a, plurality ofhigh velocity jets of elastic fluid into a receiver, said jets beingdirected, convergently with respect to each other,

at acute angles to a restricted region of a plane towards the same sidethereof but with their axes in non-parallel and non-intersectingdirections, and introducing into said jets substantially in a zone oftheir maximum convergence material to 18 be dried, thereby forming adispersion of said material flowing from said region in fluid from thejets.

9. The method of drying material comprising directing a plurality ofhigh velocity jets of elastic fluid into a receiver, said jets beingdirected, convergently with respect to each other, at acute angles to arestricted region of a plane towards the same side thereof but withtheir axes in non-parallel and non-intersecting directions and in thesame skew direction relative to a line normal to said region, andintroducing into said jets substantially in a, zone of their maximumconvergence material to be dried, thereby forming a rotating dispersionof said material flowing from said region in fluid from the jets.

10. Apparatus for drying material comprising a receiver, a nozzlearranged to discharge into the receiver, means for supplying to thenozzle an elastic fluid under pressure to produce a high velocity jetthereof from the nozzle, means for introducing into the jet material tobe dried, and elastic fluid guiding means located inside said receiver,extending rearwardly from the vicinity of formation of said jet, open atboth ends to the fluid in the receiver, spaced at least in part from thewalls thereof, and constructed and arranged so as not to be engaged bysaid jet though subject to induction through it by the jet of highvelocity flow of elastic fluid to carry the dispersion of materialformed by the jet.

11. Apparatus for drying material comprising a receiver, a nozzlearranged to discharge into the receiver, means for supplying to thenozzle an elastic fluid under pressure to produce a high velocity jetthereof from the nozzle, means for introducing into the jet material tobe dried, and

elastic fluid guiding means located inside said receiver, extendingrearwardly from the vicinity of formation of said jet, open at both endsto the fluid in the receiver, spaced at least in part from the wallsthereof, and constructed and arranged so as not to be engaged by saidjet though subject to induction through it by the jet of high velocityflow of elastic fluid to carry the dispersion of material formed by thejet, said guiding means having a restricted throat in the vicinity offormation of the jet.

12. Apparatus for drying material comprising a chamber of convexhorizontal cross-section, means for introducing into a lower portionthereof a stream of elastic fluid, means for introducing a dispersion ofthe material into said stream, the

last named means comprising material feeding means and means forsubjecting the material to a jet of elastic fluid having in at least aportion thereof a velocity of flow at least equal to the velocity ofsound in thefluid of the jet having the same pressure and temperature assaid portion of the jet, thereby to provide a fine dispersion of thematerial, means providing a substantially closed region communicatingwith the lower portion of said chamber below the region of entrance ofsaid elastic fluid, and a passage communicating with the upper portionof the chamber for removal of elastic fluid containing dried material.

13. Apparatus for drying material comprising a chamber of convexhorizontal cross-section, means for introducing substantiallytangentially into a lower portion thereof a stream of elastic fluid toprovide a spirally rising current of fluid therein, means forintroducing a dispersion of the material into said stream, the lastnamed -means comprising material feeding means and means for subjectingthe material to a letof elastic fluid having in at least a portionthereof a velocity of flow at least equal to the velocity of sound inthe fluid of the jet, having the same pressure and temperature assaidportion of the jet, thereby to provide a flne dispersionof-thematerial, means providing a substantiallyclosed region communicatingwith the lower portion of said chamber below the region of entrance ofsaid elastic fluid, and a passage communicating with prising an enlargedmixing chambenmeans for introducing into said mixing chamber saidimterial and an elastic fluid,'the latter'in'the form of a-high velocityjet, to produce in said chamber an" intimate mixture of. the materialand the seam velocity jetof elastic fluid having in at least a portionthereof a velocity of flow at least equal to the velocity of sound inthe fluid of the jet having the same pressure and temperature as saidportion of the Jet, and a tube for leading the mixture of material andfluid to said means for producing the second Jet to be dispersedthereby.

15. Th method of drying material oi viscous nature comprising feedinginto a mixing region said material and a high velocity jet'of elasticfluid to produce turbulently an intimate mixture oifisaid material andfluid having an average viscosity substantially lower than that of thematerial originally, and leading said mixture to anotherhigh velocityjet of elastic fluid to be Y dispersed thereby into a flne suspension,the secelaatic'fluid, means for producing another high on'djjet havingin at least a portion thereof a velocity of flow at least equal to thevelocity of sound in the fluid of the Jet having'the same pressure andtemperature as saidportion of the jet.

NICHOLAS N. B'I'EPHANOFF.

